1. Field of the Invention
The invention relates to a method for positioning bead cores during the building of a tire carcass of a radial tire on the first step of a tire-building machine which has an expandable carcass drum featuring a cylindrical outer circumference, two bellows supports with bellows and two core-setting devices displaceable in the axial direction of the carcass drum, whereby the core-setting devices pick up the cores from one of the sides of the carcass drum and one of the core-setting devices transports the core picked up by it to the other side of the carcass drum.
The invention further relates to a device for positioning bead cores during the building of a tire carcass of a radial tire on the first step of a tire-building machine which has an expandable carcass drum featuring a cylindrical outer circumference, two bellows supports with inflatable bellows and two core-setting devices displaceable in the axial direction of the carcass drum to pick up the cores from one side of the carcass drum, whereby one of the core-setting devices is displaceable over the carcass drum to the other side of the carcass drum.
2. Discussion of Background Information
It is known to produce green tires by one-step or two-step tire-building machines. In a two-step method, on the first step of the tire-building machine, the inner liner and subsequently the carcass ply is placed and spliced on an expandable carcass drum featuring a cylindrical outer circumference. With the drum expanded, the bead cores are set together with the core profiles. Then the projections of the carcass ply extending beyond the carcass drum are turned up around the bead cores and the core profiles, which is carried out with the aid of inflatable bellows. After the placing of further tire parts, if applicable, and the placing and rolling of sidewall profiles, the tire carcass is finished and is removed from the carcass drum now retracted. The tire carcass is transported to a second building drum via a transfer device. The belt layers are completed to form the belt assembly on a separate belt drum, and subsequently the one-piece or multi-piece tread rubber is applied. A transfer device transports the belt/tread rubber assembly to the tire carcass and positions it over the carcass. By shaping the tire carcass is joined together with the belt/tread rubber assembly and connected by rolling. In a one-step method the production of the carcass and the finishing of the green tire takes place on a single drum by completing with the belt/tread rubber assembly.
With two-step tire-building machines operating according to an expansion-drum method, the cores are set, e.g., from one side of the carcass drum in that the one core is blown over the carcass drum from left to right or vice versa with air nozzles. This measure is unpleasantly loud and works only insufficiently with cores with small core profiles. With tire-building machines operating according to the finger-ply-down method, there is no device at present that would facilitate or accelerate the setting of bead cores. The bead cores are placed into the tire-building machine left and right by hand. The cycle time of the tire-building machine is thus relatively long.
A method and a device for setting bead cores onto a tire carcass are known from EP-A2-1 295 708, in which a tire-building machine with a carcass drum is used, which is clamped on the one side so that both bead cores must be set from the free end of the drum. The two bead cores are grasped at the side of the free area of the carcass drum by one core-setting device each, whereby the one core-setting device is moved over the carcass drum in order to bring this bead core into a “parking position” on the carcass drum. As the core diameter is larger than the outer diameter of the drum, the core is first set onto holding parts arranged over the circumference of the carcass drum, and the core-setting device is removed. In order to set this core, the core-setting device grasps the core again and moves it onto the tire carcass built up in the meantime. When this core-setting device has been removed, it can be brought into its original position again on the other side of the carcass drum. To this ends it is provided that the core-setting device is assembled from segments which can open in a forcipate manner in order to be able to lift the device off the carcass drum.